Quantitative Investigation into The Link Between Irrigation Water Quality and Food Safety: Volume II

Expanded Title:

There is a growing concern of the “safety status” of South African agricultural produce, especially those that are consumed raw. If these products are contaminated they will impact not only the health of the final consumer but also that of people living next to rivers and the producers. This will immediately impact both the national and international “trading status” and cause a suspension of exports. Furthermore, there were, and still are regular articles in the local press reporting on the shocking “environmental status” of local rivers. The source of contamination of the agricultural products was identified as irrigation water that had been contaminated before irrigation took place. The health risks associated with the use of contaminated irrigation water on agricultural products thus became an increasing concern.
The main objective of solicited research project was to do a quantitative investigation into the link between irrigation water quality and food safety.
Based on the results from this research project, the microbial pollution levels of rivers and fresh produce monitored at selected sites in different provinces of South Africa over a period of 3-4 years were of an unacceptable microbiological standard and did not meet either the international or national faecal guidelines for safe irrigation or human consumption. Other potential waterborne bacterial, virus and protozoan pathogens were frequently recovered from both the water and the produce. It was concluded that there is a high risk of exposure to pathogens when water from these rivers is used to irrigate produce that is consumed raw or without any further processing steps.
In the research it was shown using phenotypic and genotypic identifications that direct water to produce linkages could be made. It was concluded that species from the surface of produce were present as a result of transfer from the contaminated irrigation water. There can now be no doubt that specific carry-over does take place. The potential of pathogenic organisms being transferred from irrigation water to the surface of fresh produce plus their ability to survive in these unfavourable conditions presents the scenario where consumers unknowingly face a high risk of being infected with harmful organisms when consuming fresh produce. Various recommendations for further research are made ranging from distribution profiles of pathogenic bacteria, seasonal variations and monitoring in irrigation water, development of effective quality assurance measures for detection of enteric viruses to investigation of effective on-farm treatment options of contaminated irrigation water.